Unify build epoch to add flag in platformio-custom.py (#7917)

* Unify build_epoch replacement logic in platformio-custom

* Missed one

.github/actions/setup-base/action.yml

@@ -11,11 +11,6 @@ runs:
         ref: ${{github.event.pull_request.head.ref}}
         repository: ${{github.event.pull_request.head.repo.full_name}}
 
-    - name: Uncomment build epoch
-      shell: bash
-      run: |
-        sed -i 's/#-DBUILD_EPOCH=$UNIX_TIME/-DBUILD_EPOCH=$UNIX_TIME/' platformio.ini
-
     - name: Install dependencies
       shell: bash
       run: |